1. Field of the Invention
The present invention relates to a heartbeat sensing device, especially to a watch-typed heartbeat sensing device.
2. Description of the Prior Art
Heartbeat sensing device is a device for detecting and displaying a heartbeat of a user. It has been widely applied in various devices for medical diagnosis and sporting purposes. By means of the heartbeat sensing device, a heartbeat is detected and displayed, thereby a user or doctor can monitor the body status of the user or patient. For example, a heartbeat sensing device is commonly installed to work in coordination with an exercise equipment. The heartbeat of the exerciser is detected and shown via a display unit of the heartbeat sensing device. Moreover, the heartbeat sensing device may be equipped with other devices like audio device, alarm and so on, so as to provide the user multiple practical functions.
Basically, a heartbeat sensing device comprises a rubber conductor which is an electrode capable of detecting a heartbeat signal and a control circuit for processing the heartbeat signal. The rubber conductor is electrically connected to the control circuit, and the heartbeat signal detected by the rubber conductor is transmitted to the processing circuit of the control circuit for processing and then displayed in a display unit.
For a wireless heartbeat sensing device, besides the rubber conductor and control circuit, it further comprises a wireless transmitting circuit which emits the heartbeat signal wirelessly to a remote receiver which is positioned within an effective distance from the heartbeat sensing device. The remote receiver receives and displays the signal.
Currently, various types of heartbeat sensing device are available in the market. Some the heartbeat sensing devices are in the form of a watch. The watch-typed heartbeat sensing device is fitted on the wrist of the user for detecting the heartbeat.
In the operation of heartbeat sensing device, the electrical connection between the rubber connector and the control circuit is a critical part that affects the effective and precise transmission of the heartbeat signal. In the past few years, the manufacturers have been aimed and devoted to develop a good electrical connection that precisely transmits the heartbeat signal with high fidelity.
In the conventional design of electrical connection, the heartbeat sensing device generally comprises a conductive plate which is mounted at the bottom of the heartbeat sensing device. Thereby, the conductive plate directly contacts the user's body and detects his heartbeat.
FIG. 1 shows a conventional watch-typed heartbeat sensing device. As shown, the heartbeat sensing device 100a comprises a display device 10a and a first conductive contact 10b at the top surface. There is a second conductive contact at the bottom of the heartbeat sensing device 110a. When the watch-typed heartbeat sensing device 100a is put on the wrist of a user, the second conductive contact directly contacts the user's wrist. When the user touches the first conductive contact 10b with the other hand, the control circuit inside the heartbeat sensing device 100a detects the heartbeat of the user and transmits a signal to the display device 10a for displaying. However, such a watch-typed heartbeat sensing device has many drawbacks, including poor electrical connection, weak heartbeat signal, low fidelity and low precision caused by poor contact between the second conductive contact and the user's wrist, surface staining, wetting, abrasion and vibration. Those problems frequently happen in watch-typed heartbeat sensing device, and affect the normal operation and shorten the service life of heartbeat sensing device.